python爬取并计算成绩

模拟登录后抓取成绩，计算绩点。

# -*- coding: utf-8 -*-  

import urllib
import urllib2
import cookielib
import re
import string

#绩点运算
class SDU:

   #类的初始化
   def __init__(self):
      #登录URL
      self.loginUrl = 'http://jwxt.sdu.edu.cn:7890/pls/wwwbks/bks_login2.login'
      #成绩URL
      self.gradeUrl = 'http://jwxt.sdu.edu.cn:7890/pls/wwwbks/bkscjcx.curscopre'
      #CookieJar对象
      self.cookies = cookielib.CookieJar()
      #表单数据
      self.postdata = urllib.urlencode({
            'stuid':'',
            'pwd':'xxxxx'
         })
      #构建opener
      self.opener = urllib2.build_opener(urllib2.HTTPCookieProcessor(self.cookies))
      #学分list
      self.credit = []
      #成绩list
      self.grades = []

   def getPage(self):
      req  = urllib2.Request(
            url = self.loginUrl,
            data = self.postdata)
      result = self.opener.open(req)
      result = self.opener.open(self.gradeUrl)
      #返回本学期成绩页面
      return result.read().decode('gbk')

   def getGrades(self):
      #获得本学期成绩页面
      page = self.getPage()
      #正则匹配
      myItems = re.findall('<TR>.*?<p.*?<p.*?<p.*?<p.*?<p.*?>(.*?)</p>.*?<p.*?<p.*?>(.*?)</p>.*?</TR>',page,re.S)
      for item in myItems:
         self.credit.append(item[0].encode('gbk'))
         self.grades.append(item[1].encode('gbk'))
      self.getGrade()

   def getGrade(self):
      #计算总绩点
      sum = 0.0
      weight = 0.0
      for i in range(len(self.credit)):
         if(self.grades[i].isdigit()):
            sum += string.atof(self.credit[i])*string.atof(self.grades[i])
            weight += string.atof(self.credit[i])

      print u"本学期绩点为:",sum/weight

sdu = SDU()
sdu.getGrades()